1. Field
The disclosed technology relates to a liquid crystal display, and more particularly, to a liquid crystal display which compensates for deviation in brightness of red, green, and blue pixels.
2. Description of the Related Technology
A liquid crystal display (LCD) displays an image by controlling the light transmittance of liquid crystals using an electric field. The LCD controls the electric field between a pixel electrode and a common electrode facing each other. An LCD display has a bottom substrate where thin film transistors (TFT) are formed to drive liquid crystals and a top substrate where color filters are formed.
The bottom substrate and the top substrate are attached to each other, and have spacers for uniformly maintaining cell spacing between the bottom substrate and the top substrate, where liquid crystal fills the cell spacing.
The top substrate includes the color filters for realizing color, black matrix for preventing light from leaking, a common electrode for controlling the electric field, and an alignment layer to align the liquid crystal. The bottom substrate includes a plurality of signal wiring lines, TFTs, pixel electrodes coupled to the TFTs, and another alignment layer for aligning the liquid crystal. In addition, the bottom substrate further includes a storage capacitor for stably maintaining the pixel voltage signal charged in the pixel electrode until a next voltage signal is charged.
An LCD display may be driven by various methods. In a vertical switching mode such as a vertical alignment (VA) mode, an electrically controlled birefringence (ECB) mode, and a twisted nematic (TN) mode, color shift is generated in a gray scale region.
In the color shift, because the wavelengths of light that pass through the red, green, and blue color filters are different from each other, the dispersion of the wavelengths are different from each other. Therefore, the transmittances of the wavelengths are different from each other.
In order to address the color shift problem, a liquid crystal panel may be given dispersion characteristics in a white state. In this technique, almost 100% of brightness of the blue pixels is used. However, only about 80% of brightness of green pixels and about 60% of red pixels is used. Therefore, overall, about 20% of brightness is lost.